The present invention relates generally to metallic, panel-type roofing systems, and more particularly to such roofing systems that include ventilation between metallic roofing panels and a roof structure or substrate.
In various types of roofing systems employing metallic panels to form the roof covering, it is important to provide for a flow of ventilation air in the space between the metallic roofing panels and the roof structure or other substrate. Such ventilation is necessary in order to substantially prevent or at least minimize the accumulation of standing condensed water, which can react with surrounding materials, such as the substrate or the metal panels themselves, and result in corrosion.
In an attempt to provide such ventilation, prior roofing systems have included a variety of arrangements for separating the metal panels from the substrate or roof structure. Such devices have included corrugated, galvanized strips, which are placed beneath the metal panel as a spacer, but it has been found that such rigid strips are somewhat difficult and time-consuming to install, as well as failing to provide adequate, free ventilation between the panel and substrate or roof structure.
Another system uses a thermoplastic sheet material that has dimples or protrusions thereon in order to maintain the proper ventilation space. Such sheets have been found to be disadvantageous due to the temperature sensitivity of thermoplastic materials, which can result in the dimples or protrusions melting and collapsing in high-temperature environments. Once such dimples or protrusions have collapsed, the ventilation space can become obstructed.
In order to overcome the above-described difficulties and disadvantages of prior roofing systems, the present invention provides a ventilated roofing assembly for covering a roof structure on a building, with the roofing assembly including a sheet-like ventilation mat adapted to be placed in an overlying relationship with the roof structure, and with the ventilation mat being of a relatively loosely woven mesh configuration, in order to allow air to flow therethrough. The mesh-type ventilation mat, which is preferably composed of extruded nylon or other thermosetting materials, is placed between an outer roofing panel and the roof structure or substrate, with a mounting member provided for securing both the ventilation mat and the roofing panel to the roof structure.
In a preferred form of the invention, the outer roofing panel includes a generally planar panel portion overlying the ventilation mat, with at least one panel flange extending generally transversely from an edge portion of the planar portion. The mounting member preferably includes a base portion disposed between the planar portion of the roofing panel and the ventilation mat, a mounting flange portion extending generally transversely relative to the base portion for generally flatly engaging the panel flange of the roofing panel, one or more fasteners extending through the base portion and the ventilation mat and into the roof structure, and an attachment for securing the mounting flange and the panel flange to one another with the planar portion of the roofing panel spaced away from the roof structure and with the ventilation mat disposed therebetween. Preferably, the attachment includes one or more attachment tabs protruding from the mounting flange portion and bent over the panel flange during installation in order to interlockingly secure the mounting flange portion and the panel flange to one another. Furthermore, the invention preferably includes one or more spacing tabs protruding from the mounting flange portion of the mounting member, with the roofing panel engaging the spacing tabs and being supported thereby in order to maintain a predetermined spaced distance between the planar portion of the roofing panel and the roof structure or substrate.
Additional objects, advantages, and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.